Radio impulse system for oscillograph calibration



Dec. 15, 1953 A. DE ROSA 2,662,977

RADIO IMPULSE SYSTEM FOR OSCILLOGRAPH CALIBRATION Original Filed Dec. 5,1942 Inventor LOUIS. A. DE ROSA Attorney Patented Dec. l5, 53

RAUM) IMPULSE SYSATEM'FOR QSCL'L- GRAPH CALEBRATIN Louis A. De Rosa,Bloomfield, N'. d., assigner `to International Telephone and TelegraphCor poration, a corporation of Maryland Continuation of applicationSerial No. 467,948, December 5, 1942. This application March '23, 1958,Serial No. 151,509

13 Claims. i

This invention relates to radio impulse sys,- tems and more particularlyto a system for generating pulses in a selected time relation inresponse to a synchronizing impulse. This application is a continuationof my earlier filed application Serial No. 467,948, led December 5,1942, now abandoned.

An object of thev invention is to provide a method andy means to producein response to a synchronizing impulse a plurality of pulses of selectedamplitude and displacement applicable for uses such as for thecalibration of the screen of a cathode ray oscillograph, and as areference marker and/or for synchronizing a vernier oscillograph.

The invention comprises generating a first series of small amplitudepulses preferably by shock excitation of a tuned circuit by energy of asynchronizing impulse, whereby a. sinusoidal Wave is produced. This Waveis clipped so as to form a rectangular Wave shape. This rectangular waveis then differentiated to form alternately positive and negative pulsesof small amplitude, the positive pulses corresponding to the leadingedges and the negative pulses corresponding to the trailing edges of therectangular wave. These pulses when passed through. a threshold clippingdevice provide a series of constant amplitude undirectional pulses.

In order to provide a second series of pulses having a greaterdisplacement, energy of the synchronizing impulse is divided into aplurality of components and each component which constitutes a new pulseis retarded a different amoimt,

preferably by amounts equal to multiples of the spacing between adjacentpulses of the rst series. I selectively control the amplitude of thepulses corresponding to these different components and mix or combinethem with the pulses of the first series, preferably before thethreshold clipping operation. The pulses of this second series beingcontrolled in time relation with respect to the pulses of the nrstseries will add to the energy of certain of the pulses thereof toproduce larger sharply defined pulses so as to set oi` in groups thepulses of the first series. By proper control of the amplitude of thepulses of the second series major and semi-major or decimal markers etc.can be produced. These pulses can be used to calibrate a panoramicoscillograph such as shown in the patent to H. G. Busignies, Patent No.2,471,408, filed October 31, 1942, and granted May 31, 1949.

Energy of the pulses of theA second series may bel selected to provide areference marker for the panoramic oscillograph and also forsynchronizing a Vernier oscillograph such as dis- .Closed `in myaforesaid copending application. ln order rto insure a pulse having asteep wavefront, the, reference marker or Vernier synchronizer pulse maybe generated in the same manner as the first series mentioned above andthe corresponding pulse thereof superimposed with the selected pulse ofthe second series.

For a better understanding of the method and means by which the ,methodmay be practicedv, reference may be had to the following detaileddescription to be read in connection with the accompanying drawings, inwhich:

Fig.. 'l is a schematic. illustration of a pulse generating lsystem inaccordance with my invention;` and Fig. 2 Ais a graphical illustrationshowing the steps of the method.

The system shown in Fig. 1 comprises an input circuit lli which may beassociated with radio or other electrical apparatus from which impulseenergy l2 may be received as a source of synchronizing. impulses. Thesynchronizing impulses `are each used to shock excite a pulse generatorle of the character disclosed in my copending application entitledTiming System, Serial No. 466,557, filed November i942, new PatentNumber 2,438,904 granted April 6, 1948, whereby a constant amplitudesinusoidal wave 2o (Fig. 2) is produced. The wave, however, need not beof constant amplitude but may be slightly damped. The generator ldincludes a limiting clipper whereby the Wave 29 is clipped along levels2l and 22 thereby producing a wave of rectangular shape. Thisrectangular wave is differentiated before leaving the generator it toproduce alternately positive and negative pulses 24 and 25. The positivepulses 2d correspond to the leading edges of the cycles of the wave2.5iwhile the negative pulses 2.5 correspond to the trailing edgesthereof.

These pulses may be passed through a threshold clipping device 3o. whichincludes a vacuum tube 32 the grid i3 of which is provided with acoupling circuit including condenser 3d and a resistor 35, the latterbeing connected to a point of negative bias C-.. The anode 36 isprovided with a posi-tive bias B+ through a resistor 3l'. A screen grid3l is grounded through a condenser 4l and subjected to a positive biasthrough resistor 43;. The output 38 of the device 89 is taken off at theanode 36 through a condenser 3.9. The threshold clipping operation ofthe device v3i) operates to provide a series of` constant amplitudeunidirectional pulses 24a such as indicated above the threshold level40.

Since this first series of pulses has a constant amplitude, it isdifcult, where the pulses are used for calibration purposes, to quicklycount the spaces between a number of these pulses. In order to providemajor and semi-major pulses so as to group the smaller pulses 24a, Iprovide a delay circuit t2 for the purposes of producing such major andsemi-major pulses from the energy of the synchronizing pulses I2. Thedelay circuit may be of any known construction, and as shown comprisesan inductance-capacity network similarly as disclosed in the abovementioned patent to H. Busignies. More particularly, the delay circuit42 comprises a long inductance coil la having a series of taps to whicha network of condensers 45 are connected in parallel arrangement. Toeach of the taps, I connect a potentiometer 46. The impedance of thepotentiometer winding is selected high compared to the impedance of thenetwork sections of the delay circuit to minimize feedback through thecommon ground connection 48. The outputs of the potentiometers aresupplied to a second control grid 5&3 of the tube 32 through a couplingcondenser 53. The grid 50 is provided through a resistor 5t with anegative bias.

When energy of the impulse i2 is applied to the delay circuit 112, theenergy divides in passing therethrough into a plurality of components,one component each passingthrough a potentiometer cit. The component 'ipassing through the first potentiometer reaches the potentiometer tap 5ithereof without having been delayed. The component 62 of the energyreceived through the tap 52 of the next potentiometer is delayed a timeinterval t1. This time interval may be taken equal to a desired multipleof the spacings between adjacent pulses 24a. As shown in Fig. 2, forexample, the time interval t1 is taken equal to five of the spacesbetween adjacent pulses ii. The successive components received throughthe taps of the potentiometers 46 are mixed with the energy of thepulses 24a in the tube 52. The components Si, 62, etc., combine with theenergy of the pulses 24a which are in exact time relation therewith toproduce large pulses tia, iiZa, etc. in which the steepness of thewave-fronts thereof are insured by the pulses 24a. That is to say, thecomponents in passing through the delaying network lose their sharpness,but the original sharpness, especially of the wave-fronts thereoi, issubstantially regained by the superimposing thereon of the correspondingpulses Zia. This results in the production at the output 38 of acalibration scale such as illustrated at tt.

Since the pulses produced by the component received through thepotentiometer taps can be controlled by selective positioning of thetaps, any desired amplitude relation of the pulses Sla, 62a, etc., canbe produced. For example, alternate pulses Sie, 53a, etc. may beselected as the largest or major pulse markers while the pulses 62a,6ta, etc., may be selected to have a lesser amplitude but greater thanpulses 24a so as to constitute semi-major or decimal markers. Theindividual control of the amplitude of the components provides further ameans for compensating for reduction of the impulse energy as it issubjected to repeated division along the delay network Q2.

In order to provide a synchronizing pulse output for the Vernieroscillograph VO and also t0 marker or synchronizing pulse.

provide a reference marker pulse for indication on the panoramicoscillograph PO of the starting point of the Vernier indication of thatpart of the range covered by the Vernier oscillograph, the followingcircuit is provided. A selecting device l is provided having a pluralityof taps 'il to 'i3 and a movable contact til adapted to be moved forselective engagement with the taps 1! through i8. The taps 7| through'ES are connected to the input connections of alternate potentiometers#le so that the energy at the taps H, l2, i3, etc. correspond to thepulses Gla, 63a, 55a, etc. By proper adjustment of the contact Bilenergy having the delay characteristics of the aforementioned pulses61a, 63a, etc. may be tapped oil? from thedelay circuit 32. This energyis applied to a Vacuum tube 32a of a threshold clipping device Sidasimilar to the device Si) hereinbefore described. The pulse series 25,25 produced by the generator lli are applied to the tube 32a throughconnection 82. The tube 32a, however, is provided with a negative bias Cgreater than tube 52 so that the pulses 2d wil1 not appear in the anodecircuit 8d. The pulse of the series 2t which corresponds in time withthe selected pulse energy applied to the tube 32e from the selectordevice I adds thereto to produce a sharply dened pulse adaptable as aTube 32a is maintained in a non-conductive condition until a pulse fromSil overcomes the C- bias to thereby render tube 32a. conductive. Sincethe contact til is in engagement with thetap 12, this pulse 65 willcorrespond in time with the pulse @3a. r)This use of the pulses 24insures a steep wavefront for the pulse 8%.

It will be observed that movement of thev contact @ai from tap to tap ofthe device 70 will cause the pulse 85 to move by jumps from major pulseto major pulse, that is, from pulse 63a to pulse 65a, etc. It will beunderstood, however, that the movement of the pulse 85 may be reduced tomuch smaller steps by providing taps for the device v'FEB one for eachnetwork section of the delay device 132.

The pulse 235 when used for synchronizing the sweep potential of theVernier oscillograph is applied through connection 36 to the sweepcircuit SC of the Vernier oscllograph. Energy of the pulse 85 may alsobe used as a reference marker by applying the energy through connection87 to the vertical deection plates of the panoramic oscillograph PO. Thepulse 85 will thereby indicate on the panoramic oscillograph the pointat which the sweep of the Vernier oscilloscope commences. The intervalcovered by the sweep of the Vernier may be arranged to equal 15 of thespaces denied by the pulses Ma. Thus, when the Vernier sweep is shiftedalong the trace line of the panoramic oscillograph in groups of l() suchspaces there will be an overlapping of 5 spaces by the trace line on theVernier oscillograph. Thus, should a pulse appear near the end of thesweep of the Vernier for one position of the device it, the pulse may belocated more nearby the center of screen of the Vernier oscillograph byshifting the device 'ED one position.

While I have disclosed a specific apparatusv indicating on the panoramicoscillograph theV timing Vof the Vernier oscillograph, it will beunderstood that the form hereinlillustrate'd and asse-,cvs

L eseribed is 'given by way of example only and not as limiting to theobjects of the invention and the appended claims.

What I claim is:

l. A method ci generating in response to a synchronizing impulse aplurality of calibration pulses comprising producing in synchronism withsaid impulse a rst series of pulses having a given spacing betweenadjacent pulses, deriving from energy of the synchronizing impulse aseries of discrete pulse components, retarding said pulse componentsdiierent multiples of the spaces between the pulses of said firstseries, and mixing the two series of pulses so that the second series ofpulses add to those pulses of said first series corresponding in time toprovide a calibration pattern.

2. rihe method denned in claim l wherein the amplitudes ci the pulses ofthe. second series are individually controlled to selectively producelarge and small pulses thereby producing when mixed with the firstseries of pulses major and semi-major pulse markers for given points oftime.

3. A method of producing a sharply dened A ulse selectively displacedwith respect to a synchronizing impulse comprising generating a se `iesof pulses in response to said impulse, deriving from said synchronizingimpulse a series n-:Zividually independent components, recomponents byindividually different amounts, and combining a component having adesired retardation with a corresponding pulse of nrst named series.

fl. A method of producing a sharply dened pulse selectively displacedwith respect to a synchronizing impulse comprising producing insynchronism with said impulse a rst series or" pulses having a givendisplacement between adjacent pulses, deriving from said synchronizingimpulse a series of descrete pulse components, retarding said pulsecomponents different multiples of the spaces between the pulses of saidrst series, selecting one of the pulse components of the second serieshaving a desired displacement, and combining the selected pulse with thecorresponding pulse of said rst series or pulses.

5. A system for producing in response to a synchronizing impulse aplurality of calibrating pulses comprising means to generate in responseto said impulse a first series of pulses having a given spacing andamplitude, a delay device pro vided with a plurality of outlets, eachoutlet including means for controlling the amplitude of pulses passedtherethrough, said device being arranged to divide the energy of thesynchronizing impulse into a plurality of components one each to be fedthrough one of said outlets, said device being adapted to retard eachcomponent a different amount so as to provide a second series of pulseshaving a displacement between adjacent pulses equal to a multiple of thedisplacement between adjacent pulses of said iirst series, and means formixing the two series or" pulses so that the pulses of the second seriesadd to corresponding pulses of said rst series.

6, The system defined in claim 5 wherein said mixing device includesmeans to threshold clip the pulse potentials supplied thereto.

'7. The system defined in claim 5 wherein the amplitude controllingmeans associated with the outlets or" said delay device comprisepotentiometers, said potentiometers being adjustable to provide thesecond series of pulses with pulses of large and small amplitudes, andthe mixing means is provided withY means for threshold clipping thepulse. potentials so that the output thereof produces minor, major andsemi-major pulses in a given scale calibration pattern.

3. A system for producing a sharply defined pulse selectively displacedwith respect to a synchronizing impulse comprising means to generate aseries of pulses in response to said impulse, means to retard bydiierent amounts components of the energy of said impulse, means toselectively tap oir from the energy retarding means of at least onepulse energy components retarded a desired displacement with respect tosaid impulse, and means to combine the tapped-off energy with a pulse ofsaid series to produce a pulse shape having a given displacement withrespect to said impulse equal to the retardation of said tappedoienergy', the pulse ci said series operating to sharpen the pulse shapeof said tapped-@ii energy.

9. rlhe system defined in claim 8 wherein the retarding means isprovided with taps so disposed as to provide tap-off points for retardedenergy displaced amounts equal to multiples of the displacement betweenadjacent pulses of said series.

10. A radio impulse system comprising a source of synchronizingimpulses, means to generate in response to an impulse of said source anrst series of pulses, a delay device provided with a plurality ofoutlets to divide the energy of the synchronizing impulse into aplurality of components one each to be fed through one or said outlets,said device being adapted to retard each component a different amount soas to provide a second series of pulses having a displacement betweenadjacent pulses equal to a multiple of the displacement between adjacentpulses oi said nrst series, means for mixing the two series of pulses sothat the second series of pulses add to corresponding pulses of saidiirst series to provide a calibration pattern, means adjustable toselectively tap off from said delay device energy of one of the pulsesof said second series, and means to combine the tapped-ofi` energy witha pulse oi' said rst series to produce a pulse shape having adisplacement with respect to said impulse equal to the retardation ofsaid tapped-off energy, the displacement of said pulse shape beingdetermined by the adjustment of said selective tap-on" means.

11 A system for producing in response to a synchronizing impulse aplurality of Calibrating pulses, comprising means to generate a firstseries of pulses in response to said impulse, means to retard bydifferent amounts components of the energy of said impulse, so as toprovide a second series of pulses having a displacement between adjacentpulses equal to a multiple of the displacement between adjacent pulsesof said rst series, and means for mixing the two series of pulses sothat the pulses of the second series add to the corresponding pulses ofsaid rst series.

12. In a radio impulse system in which radio pulses are received andsupplied to a panoramic oscilloscope and a Vernier oscilloscope, asource of low frequency pulses, the combination of a source of periodicpulses having a frequency higher than said source of low frequencypulses, a mixer having an output circuit and a pair of input circuits, aconnection for supplying low frequency pulses to one input circuit ofsaid mixer, a connection ior supplying high frequency pulses from saidhigh frequency source to the other input circuit of said mixer, saidmixer serving to pass to said output circuit only the high frequencypulses which coincide with low frequency pulses. a sweep generator forthe Vernier oscilloscope controlled by the pulses in the output circuitof said mixer, and a variable phase shifter included in the connectionfrom said source of low frequency pulses to said mixer for adjustablytiming the pulses in the output circuit of said mixer.

13, In a radio impulse system in which radio pulses are received andsupplied to a panoramic oscilloscope and a Vernier oscilloscope, asource of low frequency pulses, the combination of a source of periodicpulses having a frequency higher than said source of low frequencypulses, a mixer having an output circuit and a pair of input circuits, aconnection for supplying said low frequency pulses to one input circuitof said mixer, a connection for supplying high frequency pulses fromsaid high frequency source to the other input circuit of said mixer,said mixer serving to pass to said output circuit only the highfrequency pulses which coincide with low frequency pulses, a sweepgenerator for the Vernier oscilloscope controlled by the pulses in theoutput circuit of said mixer, and means connected to the output of saidmixer for producing a marker indication on said panoramic oscilloscope,and a variable phase shifter included in the connection from said sourceof low frequency pulses to said mixer for adjustably timing the pulsesin the output circuit of said mixer.

LOUIS A. DE ROSA.

References Cited in the file 0f this patent UNITED STATES PATENTS NumberName Date 2,403,278 Hershberger July 2, 1946 2,417,136 smith Mar. 11,1947 2,423,682 Busignies July l, 1947 2,423,644 Evans July 8, 194'!2,450,341 Hershloerger Sept. 28, 1943

